1. Technical Field
The invention includes embodiments that relate to an article for storing hydrogen. The article may be an electrode that can store hydrogen.
2. Discussion of Art
An electrochemical system, such as a fuel cell or a battery, is capable of efficient energy conversion and can be used in a variety of applications. These applications may include transportation applications, portable power sources, home power generation, and large-scale power generation. A fuel cell can generate energy as long as fuel is supplied. A battery, by contrast, is limited to the amount of stored energy it can hold—and some can be recharged thereafter. Fuel cell systems may consume oxygen and hydrogen to emit water and energy. The energy may be in the form of electric power and heat.
In a fuel cell device, hydrogen is supplied to the anode, or can be stored within the anode, while an oxidant is supplied to the cathode. Hydrogen can also be stored at the negative electrode of a battery. For example, metal hydrides may be used as a material for the negative electrode of a battery. Such batteries may include air-metal hydride batteries and Ni-metal hydride batteries. Metal hydride materials may be activated before being integrated into electrodes. Untreated metal hydrides may form an oxide layer on the surface of the metal hydride. The oxide layer may lead to poor charging efficiency and low discharge capacity of the electrode. An activation process removes the oxide layer from the surface of the metal hydride. Untreated metal hydrides may sometimes need additional electrochemical charge-discharge cycles to reach the maximum storage capacity of the metal hydride material and the initial discharge capacity may be too low to run the electrochemical system as efficiently as desired.
Oxide formation on the surface of the metal hydride may be reduced or prevented by hot alkali treatment, acid treatment, and chemical reduction method using reductants in alkali solution. These methods may treat the metal hydride powder. Further activation of the metal hydride electrode may not be done if the powder itself was activated prior to the electrode fabrication. Similarly when the fabricated metal hydride electrode is activated, the metal hydride powder itself may not be activated.
It may be desirable to have an apparatus or system with properties and characteristics that differ from those properties of currently available apparatus or system. It may be desirable to have a method that differs from those methods currently available.